Bring a medium pot of water to a full boil. While the water is coming to a boil, prepare an ice bath with a large bowl, ice cubes and water. When the water is boiling, carefully add onions into the pot and boil for 1-2 minutes.,,______,,In a large skillet or saute pan, melt the butter over medium heat. Add the onions to the pan and turn heat down to medium-low. Allow onions to brown in the butter until they are golden and tender when pierced with a sharp paring knife. When ready, drizzle with the Balsamic and swirl the pan to coat the onions. Serve hot.